1. Field of the Invention
The present invention relates to a device and method for rewriting main memory data in a deactivating period.
2. Description of the Related Art
Recently, various information processing devices, typified by personal computers (PC), are used by many users. Information processing devices are provided with a plurality of deactivation schemes to adapt to various usage aspects of users. The simplest deactivation scheme is merely to power off an information processing device (i.e., shutdown). Often, however, volatile storage media excellent in access rate are used for main memories of information processing devices. In this case, since main memory data is lost when the information processing device is powered off, much time is required before the information processing device is restored to its previous working state from resumption of operation. That is, shutdown is unsuitable for a usage aspect in which a user temporarily suspends a work.
Meanwhile, other deactivation schemes (“suspend”, “standby”, and so forth) capable of quickly being restored to its previous working state from resumption of operation by continuing power supply to the main memory in a power-saving mode to maintain main memory data has been also known. Although the suspend consumes power to some extent during a deactivating period, the suspend is useful in that the previous working state can be quickly restored from resumption of the operation, as described above. Further, “Linux Software Suspend”<URL: http://lxr.linux.no/linux+v.2.6.26/Documentation/power/swsusp.txt> (hereinafter simply referred to as related art) presents a deactivation scheme (“hibernation” or “software suspend”) capable of quickly being restored to its previous working state from resumption of operation and suppressing power consumption, compared to the suspend, by temporarily saving main memory data in an auxiliary storage device, for example, formed of a nonvolatile storage medium, before deactivation of the information processing device.
Further, Japanese Patent No. 3882452 (page. 12, FIG. 2) presents an operation resumption scheme intended to prevent failure to receive data (packets) via a network in a period (hereinafter simply referred to as activation preparation period) from when a communication device is powered on until when a central processing unit (CPU) completes activation. The communication device is provided with a sub memory means separate from a main memory means, and data received during the activation preparation period is temporarily stored in the sub memory means. After completion of activation of the CPU, the data stored in the sub memory means is copied by the main memory means. Thus, according to the communication device disclosed in Japanese Patent No. 3882452, failure to receive data during the activation preparation period can be prevented.
Further, a method of synchronizing a call information server disclosed in JP-A 2006-270581 (KOKAI) (page. 7, FIG. 1) attains redundancy by forming a call information server by an active server and a standby server physically separated from each other, and uses a remote direct memory access (RDMA) function to synchronize data between the two servers. Thus, according to the method of synchronizing the call information server disclosed in JP-A 2006-270581 (KOKAI), the standby server as a substitute means continues to operate when the active server goes down for some reason, and thereby high reliability can be expected.
For example, according to “software suspend (hibernation)” disclosed in the related art, an information processing device is capable of quickly being restored to its previous working state from resumption of operation, and preventing power consumption during a deactivating period. The main memory data may include data types such as data in which expiration data is set, or data the contents of which are changed with passage of time. That is, when a deactivating period of the information processing device is relatively long, the main memory data held in a nonvolatile storage medium may partially lapse, or its contents may become old. Accordingly, even when operation of the information processing device is resumed, data belonging to the data type needs to be updated, which may prevent the information processing device from being restored to its previous working state smoothly. It is to be noted that means for rewriting main memory data maintained in a nonvolatile storage medium in a deactivating period of an information processing device is disclosed neither in Japanese Patent No. 3882452 nor JP-A 2006-270581 (KOKAI).